1. Field of the Invention
The invention relates to a differential load amplifier for a piezoelectric sensor. The invention is applicable to all devices utilizing piezoelectric sensors, and particularly to devices for measuring the vibrations of an engine by means of a piezoelectric accelerometer.
2. Summary of the Prior Art
It is known to measure the vibrations of an engine by means of a piezoelectric sensor associated with a load amplifier, the purpose of the load amplifier being to convert into a voltage the electrical load delivered by the piezoelectric sensor. In the case of equipment on an engine or in an industrial environment, an unwanted signal, termed a common mode voltage, generally superimposes itself on the signal to be measured, and elimination of the unwanted signal is achieved by using a differential structure comprising a differential piezoelectric sensor in association with a differential load amplifier. The known differential load amplifiers usually include two operational amplifiers mounted as integrators and require a strict pairing of two integration capacitors, which can be achieved only by means of a lengthy and costly sorting of components.